added BendyLine

interface/src/BendyLine.cpp

@@ -0,0 +1,119 @@
+//
+//  BendyLine.cpp
+//  interface
+//
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+
+#include "BendyLine.h"
+#include "Util.h"
+#include "world.h"
+
+const float DEFAULT_BENDY_LINE_SPRING_FORCE  =  10.0f;
+const float DEFAULT_BENDY_LINE_TORQUE_FORCE  =  0.1f;
+const float DEFAULT_BENDY_LINE_DRAG          =  10.0f;
+const float DEFAULT_BENDY_LINE_LENGTH        =  0.09f;
+const float DEFAULT_BENDY_LINE_THICKNESS     =  0.03f;
+
+BendyLine::BendyLine(){
+
+    _springForce   = DEFAULT_BENDY_LINE_SPRING_FORCE;
+    _torqueForce   = DEFAULT_BENDY_LINE_TORQUE_FORCE;
+    _drag          = DEFAULT_BENDY_LINE_DRAG;
+    _length        = DEFAULT_BENDY_LINE_LENGTH;
+    _thickness     = DEFAULT_BENDY_LINE_THICKNESS;
+    
+    _gravityForce  = glm::vec3(0.0f, 0.0f, 0.0f);
+    _basePosition  = glm::vec3(0.0f, 0.0f, 0.0f);	
+    _baseDirection = glm::vec3(0.0f, 0.0f, 0.0f);  
+    _midPosition   = glm::vec3(0.0f, 0.0f, 0.0f);          
+    _endPosition   = glm::vec3(0.0f, 0.0f, 0.0f);          
+    _midVelocity   = glm::vec3(0.0f, 0.0f, 0.0f);          
+    _endVelocity   = glm::vec3(0.0f, 0.0f, 0.0f);  
+}
+
+void BendyLine::reset() {
+
+    _midPosition = _basePosition + _baseDirection * _length * ONE_HALF;          
+    _endPosition = _midPosition  + _baseDirection * _length * ONE_HALF;          
+    _midVelocity = glm::vec3(0.0f, 0.0f, 0.0f);          
+    _endVelocity = glm::vec3(0.0f, 0.0f, 0.0f);  
+}
+
+void BendyLine::update(float deltaTime) {
+
+    glm::vec3 midAxis = _midPosition - _basePosition;
+    glm::vec3 endAxis = _endPosition - _midPosition;
+
+    float midLength = glm::length(midAxis);        
+    float endLength = glm::length(endAxis);
+
+    glm::vec3 midDirection;
+    glm::vec3 endDirection;
+    
+    if (midLength > 0.0f) {
+        midDirection = midAxis / midLength;
+    } else {
+        midDirection = _baseDirection;
+    }
+    
+    if (endLength > 0.0f) {
+        endDirection = endAxis / endLength;
+    } else {
+        endDirection = _baseDirection;
+    }
+    
+    // add spring force
+    float midForce = midLength - _length * ONE_HALF;
+    float endForce = endLength - _length * ONE_HALF;
+    _midVelocity -= midDirection * midForce * _springForce * deltaTime;
+    _endVelocity -= endDirection * endForce * _springForce * deltaTime;
+
+    // add gravity force    
+    _midVelocity += _gravityForce;
+    _endVelocity += _gravityForce;
+
+    // add torque force
+    _midVelocity += _baseDirection * _torqueForce * deltaTime;
+    _endVelocity += midDirection   * _torqueForce * deltaTime;
+    
+    // add drag force
+    float momentum = 1.0f - (_drag * deltaTime);
+    if (momentum < 0.0f) {
+        _midVelocity = glm::vec3(0.0f, 0.0f, 0.0f);
+        _endVelocity = glm::vec3(0.0f, 0.0f, 0.0f);
+    } else {
+        _midVelocity *= momentum;
+        _endVelocity *= momentum;
+    }
+        
+    // update position by velocity
+    _midPosition += _midVelocity;
+    _endPosition += _endVelocity;
+
+    // clamp lengths
+    glm::vec3 newMidVector = _midPosition - _basePosition;
+    glm::vec3 newEndVector = _endPosition - _midPosition;
+
+    float newMidLength = glm::length(newMidVector);
+    float newEndLength = glm::length(newEndVector);
+    
+    glm::vec3 newMidDirection;
+    glm::vec3 newEndDirection;
+
+    if (newMidLength > 0.0f) {
+        newMidDirection = newMidVector/newMidLength;
+    } else {
+        newMidDirection = _baseDirection;
+    }
+
+    if (newEndLength > 0.0f) {
+        newEndDirection = newEndVector/newEndLength;
+    } else {
+        newEndDirection = _baseDirection;
+    }
+    
+    _endPosition = _midPosition  + newEndDirection * _length * ONE_HALF;
+    _midPosition = _basePosition + newMidDirection * _length * ONE_HALF;
+}
+
+

interface/src/BendyLine.h

@@ -0,0 +1,52 @@
+//
+//  BendyLine.h
+//  interface
+//
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+#ifndef hifi_bendyLine_h
+#define hifi_bendyLine_h
+
+#include <SharedUtil.h>
+#include <glm/glm.hpp>
+#include <glm/gtc/quaternion.hpp>
+
+class BendyLine {
+public:
+    BendyLine();
+    
+    void update(float deltaTime);
+    void reset();
+    
+    void setLength       (float     length       ) { _length        = length;       }
+    void setThickness    (float     thickness    ) { _thickness     = thickness;    }
+    void setSpringForce  (float     springForce  ) { _springForce   = springForce;  }
+    void setTorqueForce  (float     torqueForce  ) { _torqueForce   = torqueForce;  }
+    void setDrag         (float     drag         ) { _drag          = drag;         }
+    void setBasePosition (glm::vec3 basePosition ) { _basePosition  = basePosition; }
+    void setBaseDirection(glm::vec3 baseDirection) { _baseDirection = baseDirection;}
+    void setGravityForce (glm::vec3 gravityForce ) { _gravityForce  = gravityForce; }
+    
+    glm::vec3 getBasePosition() { return _basePosition; }
+    glm::vec3 getMidPosition () { return _midPosition;  }
+    glm::vec3 getEndPosition () { return _endPosition;  }
+    float     getThickness   () { return _thickness;    }
+    
+private:
+
+    float     _springForce;
+    float     _torqueForce;
+    float     _drag;
+    float     _length;
+    float     _thickness;
+    glm::vec3 _gravityForce;
+    glm::vec3 _basePosition;				
+    glm::vec3 _baseDirection;				
+    glm::vec3 _midPosition;          
+    glm::vec3 _endPosition;          
+    glm::vec3 _midVelocity;          
+    glm::vec3 _endVelocity;  
+};
+
+#endif